Solar proton fluxes have been measured by satellites for over forty years (1963-2005). Several satellites, including the NASA Interplanetary Monitoring Platforms (1963-1993) and the NOAA Geostationary Operational Environmental Satellites (1994-2005), have been used to compile this long-term dataset. Some solar eruptions lead to solar proton events (SPEs) at the Earth, which typically last a few days. High energy solar protons associated with SPEs precipitate on the Earth's atmosphere and cause increases in odd hydrogen (HOx) and odd nitrogen (NOy) in the polar cap regions (greater than 60 degrees geomagnetic). The enhanced HOx leads to short-lived ozone depletion (~days) due to the short lifetime of HOx constituents. The enhanced NOy leads to long-lived ozone changes because of the long lifetime of the NOy family in the stratosphere and lower mesosphere. Very large SPEs occurred in 1972, 1989, 2000, 2001, and 2003 and were predicted to cause maximum total ozone depletions of 1-3%, which lasted for several months to years past the events. These long-term ozone changes caused by SPES are discussed.